PSAT Math Multiple-Choice Question 838: Answer and Explanation

Question: 838

The approximate relationship between Kelvin (K) and degrees Celsius (C) is given by this equation:

K = 273 + C

The freezing point of water is 0 degrees Celsius, and the boiling point of water is 100 degrees Celsius. What are the approximate freezing and boiling points of water in Kelvin?

• A. Freezing: 0; boiling: 100
• B. Freezing: -273; boiling: -173
• C. Freezing: 273; boiling: 373
• D. Freezing: 473; boiling: 573

Correct Answer: C

Explanation:

(C) Plug the freezing point of water in degrees C into the equation:

K = 273 + C
K = 273 + 0 = 273

Choice (C) is the only option that has 273 for the freezing point. You can also plug in 100 for the boiling point in degrees C. You will get 373 as the result.